When performing closed annulus drilling operations, typically referred to as managed pressure drilling, underbalanced drilling, mud cap drilling, air drilling and mist drilling, a rotating control device (RCD), also referred to as a rotating drilling device, rotating drilling head, rotating flow diverter, pressure control device and rotating annular, may be used to divert drilling fluids returning from the well into chokes, separators and other equipment. The RCD may function to close off the annulus around a drill string during drilling operations. The sealing mechanism of the RCD, typically referred to as a seal element or packer, is operable to maintain a dynamic seal on the annulus, enabling chokes to control pressure of the annulus at the surface drilling operations. The seal element further allows drilling to continue while controlling influx of formation fluids.
The seal element may be made of a molded elastomeric packing material that includes different elastomeric compounds selected for different drilling applications. In some applications, the seal element rotates with the drill pipe and, in other applications, the seal element remains stationary while the drill pipe rotates within. As may be appreciated, the condition of the seal element is important to the operation and ongoing integrity of the RCD. However, the rotation and reciprocation of the drill pipe during drilling operations, often in conjunction with applied annulus pressure, may cause the seal element to wear such that the seal provided by the seal element degrades over time.
Conventional methods of monitoring wear in a seal element may involve physical testing of the seal element in a lab environment to determine the amount of degradation of the seal element based on the number of drill pipe tool joint passes and drill pipe rotational speed. The amount of degradation is then extrapolated to estimate how long the seal element can be used in the field, either based on a maximum amount of time, maximum drill pipe rotational speed or number of drill pipe tool joint passes. The wear and degradation, however, may be unpredictable using this method due to the varying surface conditions, and speed of reciprocation and rotation of the drill pipe. As a precautionary measure, the seal element may be changed prematurely leading to costly downtime of the drilling rig. An unexpected failure of the seal element may also lead to drill rig downtime and, in extreme cases, a release of annulus pressure that may result in the flow of drilling fluids into the surrounding environment.